Knitting head for knitting machines



1950 B. w. LERCH 2,520,010

KNITTING HEAD FOR KNITTING MACHINES Filed Sept. 11, 1947 lA/VEN TOR B W LERCH A TTORNEV Patented Aug. 22, 1950 KNITTING HEAD FOR KNITTING MACHINES Brooke VJ. Lerch, Baltimore, Md., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application September 11, 1947, Serial No. 773,426

This invention relates to knitting heads for knitting machines, andmore particularly to knitting heads in which the knitting needles are prevented from being disengaged from the needle jacks during the knitting operations.

In general, knitting heads consist of a plurality of knitting, needles which are simultaneously reciprocated and rotated at predetermined speeds so as to combine a plurality of textile threads into a tubular knitted web. This knitted web is utilized in many ways, one of the more common being to apply it as a textile covering around a conductor being continuously advanced along the central axis of the knitting head. The knitting operation of the needles in forming the knitted web creates a definite load or thrust on each of the needles, which depends mainl on the size of the textile threads being used and the type of stitch pattern involved.

Each of the needles is provided with an car on the lower end thereof which engages a bifurcated end of an associated needle jack by means of which the needles are reciprocated. In knitting heads in use at the present time, substantial portions of the upper ends of the needle jacks are unsupported, and it was found that when the knitting operation employed more than the normal number of threads or slightly heavier gauge threads, or was performed at a higher speed, the load on the knitting needles under such knitting conditions caused the ear of the needle to spring out of the slot in the jack. In addition, centrifugal force acting on the unsupported upper ends of the needle jacks tends to throw the upper ends outwardly, which action may cause the ends of the needles to slip out of the slots in the ends of the needlejacks. Therefore, it is desirable to provide the knitting head with means for preventing the disengagement of the needles and the jacks during knitting operations.

An object of the invention is to provide new and improved knitting heads for knitting machines.

Another object of the invention is to provide a knitting head wherein positive engagement of the knitting needles and needle jacks is maintained regardless of the size threads employed therein or the speed at which a knitting operation is performed.

A knitting head embodying certain features of the invention comprises a jack cylinder having a plurality of needle jacks reciprocably mounted around the periphery thereof, a tubular bearing surrounding the jack cylinder to maintainthe 2 Claims.

2 v I needle jacks in their respective slots and of'suc length that it supports the upper ends of the needle jacks as they are reciprocated. Theupper end of each needle jack is bifurcated to receive the end of a correspondin knitting needle slidably mounted in longitudinal slots provided in a needle cylinder secured in tandem to the jack cylinder. An ear is provided on the bifurcated end of each needle jack which extends upwardly therefrom so as to slidably engage a counterbore provided in a needle bearing secured on the needle cylinder. The needle 'jack bearing and the counterbore of the knittingv needle bearing serve to maintain positive engagement between the needle jacks and the needles during high speed knitting operations or knitting operations which produce a slight overload on the knitting needles.

A clear understanding of the invention will be had from the following detailed description of a specific embodiment thereof, when read in conjunction with the appended drawing, in which the single figure in an enlarged, vertical, sectional view showing a knitting head embodying features of the invention. 7

Referring now to the. drawing, the numeral It! indicates generally a gear box of a conventional knitting machine (not shown), which is arranged to revolve a jack cylinder H and a. hollow spindle l2 about the common axis of a knitting head indicated generally at [3. The gear box [0 is arranged to drive the jack cylinder and the spindle in the same direction but at different rates of speed, in accordance with well known principles involved inknitting machine practice. The complete knitting. mechanism, to which this invention is applied is disclosed in detail in Lerch et al. Patent 2,236,183 and Brillhart Patent 2,239,378, and only as much of this mechanism is disclosed and described hereinafter as is necessary for a full understanding of the present invention.

A pair of wobbler cams |4l4 are secured angularly to the spindle I 2 so that when the spindle is rotated they serve to reciprocate a plurality of needle jacks l5-l 5 positioned slidably in longitudinal slots l6-l6 provided along the periphery of the jack cylinder H. A tubular bearing IT is positioned around the jack cylinder I I to maintain the needle jacks [5-45 in their respective slots as they are reciprocated by the wobbler cams. When the jack cylinder II is rotated, the centrifugal force acting on the upper ends of the needle jacks tends to throw the upper ends .of the needle jacks outwardly away? from the .tubular web 3 I.

central axis of the knitting head I3. To support the needle jacks against the effect of this centrifugal force, the upper end of the tubular bearing I1 is extended substantially beyond the upper end of the jack cylinder II 50 that the entire straight portion I8 of the needle jacks I-I5 is supported throughout the entire stroke of the jack from the full line position shown on the drawing to their broken line position.

Each of the needle jacks I5I5 is provided with a bifurcated end arranged to receive an ear 22 formed on the lower end of each of an equal number of knitting needles 2323 slidably positioned in longitudinal slots 2424 provided in a needle cylinder 25. The needle cylinder 25 is secured to a tubular hub 26 provided integrally with a head 21 secured to the upperend of the jack cylinder II, so that the longitudinal-slots 24-24 thereof are aligned vertically with *the longitudinal slots I6-I6 provided in the jack cylinder.

.the needle jacks I5-I5 are rotated-simultaneously. about the centralaxis of .the knitting head I.3:and reciprocated arpredeterminednumber of .times per revolution of the needle cylinder 25.

Uponlthesimultaneous rotation and reciprocation of the knitting needles.23--23,. they engage a plurality of textile threads 303Il, which are drawn from suitable supply cops (not shown) and disposed-in a symmetrical pattern around the central axis or the needle cylinder, andiforma The tubular web 3| formed .by theknitting needles 2323 may be applied as a covering 32 around a conductor 33 being advanced at a constant rate of speed by a suitable capstan (not shown) through the central bores provided in the needle cylinder 25, the hub 26 of the jack cylinder I I and the hollow spindle I2.

The knitting operation performed by the needles 23-23 in forming the tubular web 3| produces a Working load on each of the knitting needles, which load is transferred longitudinally. .along the.knitting needles to the ears 22-22 which are engaged by the bifurcated ends.202fl of the needle jacks I5I.5. This working load tends to pull the ears 2222 of the knitting needles out of engagement with the bifurcated ends of the needle jacks. The needle jacks ,I5I5 mustbe quite small in cross-section in 'lifeof the knitting head I3.

As a result of this resilient nature of the needle jacks I5I5, slight overloads encountered in the knitting operation of the needles tend to spring the upper ends of the needle jacks outwardly and to disengage the ears 22-22 of the needles from the bifurcated ends thereof. In order to maintain positive engagement of ;the

ears 22-22 within the respective bifurcated'end ofthe needle jacks, vertical ears 34-34 are formed on the bifurcated ends of the needle jacks :I5I5, .which slidably-engage a counterbore 35 provided in'a split collar 36. The collar -36is poparticular type of insulating covering 32 as it is desired to apply on the conductor 33. In other words, the type of covering selected automatically determines the number of knitting needles 23--'23 required, the number and size of textile threads30-4O to be employed, the speed at which the needle cylinder is to be rotated, and the speed at which the Wobbler cams are to be driven in order to provide theproper reciprocation of the needle jacks I5I5 and the needles 2323. Obviously, it may happenthat the selected type of covering 32 may require slightlylheavierrgauge threads than those used in normal knitting operations. In addition, it may require the use (if more textile threads thannormally used in'the knitting operation or it may require the speed of the knitting operation to .be increased. All'these factors tend to overload the knitting needles and thereby develop an increased strain on the joints formed by the ears of the knittinglneedles and .the bifurcated end of the needle jacks. In addition, the increased speed of the knittingoperation results in a substantial increase in'the effect of centrifugal force over "that normally acting on the needle jacks. The combination of the increased working load'on the needles and the increased centrifugal force acting on the needle jacks tends to spring the ears of the needles out of engagemnt with the bifurcated ends of their associated needle jacks. However, since the length of the tubularbearing" I I is such that it supports the entire straight portion I8 of the needle jacks during their'full operating stroke and the ears '3434, provided on thebifurcated ends of the needle jacks slidably engage the counterbore 35 of the split c01lar36, a positive engagement between the knitting'needles and the needle jacks is maintained throughorit-thedmitting operation despite the effect of centrifugal force acting on the upper'ends of the needle 'jacks. In this way the knitting head is rendered capable of performing a wider variety'of knitting operations.

What is claimed is:

1. A knitting head'for knitting machines including a rotatable jack cylinder having a.plurality of longitudinal slots disposed around'the periphery thereof, 'a needle jack slidably positioned in each slot of said'needle cylinder, means for simultaneously rotating and reciprocatingithe needle jacks, a .needle cylinder secured in'tandem on the upper end of the jack cylinder andhaving a plurality of longitudinal slots disposed around the periphery thereof whichare aligned with the slots in the jack cylinder and a knitting needle slidably positioned in each slot of "said needle cylinder, the upper end of each iof said needle jacks extending upwardlyan'd converging inwardly to engage the lower end of a'corresponding knitting needle, the improvement Which'comprises a tubular bearing for maintaining the needle jacks in their respective slots whenthcy are rotated and reciprocated, said'tubularbearing being of such length that it extends substantially above the jack cylinder to support the portion of the needle jack which is reciprocated above the and of the "jack "cylinder, anupwardly extending ear provided on the end of the jack engaging the end of the needle, and an annular bearing provided on the needle cylinder for slidably engaging the ears provided on the end of the needle jacks, whereby the needles are prevented from becoming disengaged from the needle jacks by the action of centrifugal force when the needles and jacks are rotated.

2. A knitting head for knitting machines including a vertically positioned jack cylinder having a plurality of longitudinal slots therein, a needle jack slidably positioned in each slot of said jack cylinder, a needle cylinder secured in tandem on the upper end of the jack cylinder and having a plurality of longitudinal slots therein aligned with the slots in the jack cylinder and a knitting needle slidably positioned in each slot of said needle cylinder, the upper end of said needle jacks extending upwardly beyond the jack cylinder and converging inwardly so as to engage the lower end of their respective knitting needles, the improvement which comprises an upwardly extending ear formed on the upper end of each jack, a tubular bearing enclosing said jack cylinder and extending above the upper end of the EZEFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 451,286 Winlund Apr. 28, 1891 461,211 Winlund et a1 Oct. 13, 1891 2,298,812 Stover Oct. 13, 1942 2,348,932 Scranton May 16, 1944 2,406,525 Bardsley Aug. 27, 1946 

